1. Field of the Invention
The present invention relates to an electrified tape for use in the domain of farming or cattle enclosure fences.
2. Background and Relevant Materials
To keep cattle inside a grazing-ground or pasture, farmers are increasingly attracted by the use of electrified fences disposed at the periphery of the pasture. The advantage of an electrified fence over simple barbed wire is that the cattle are repelled by the presence of the high voltage so that the animals are prevented from being hurt by coming too close to the fence.
For obvious safety reasons, the high voltage consists only of a capacitive charge, and therefore any contact with the fence kept at a high potential produces a very low current discharge which is harmless both for humans and animals.
Though still widely in use, the electrified barbed wire is attended by many inconveniences. It is difficult to put up by reason of its inherent stiffness, and furthermore its use as a temporary fence is precluded for it is difficult to coil it up. Finally, due to its specific conception, this type of fence is dangerous since in most instances it is scarcely visible.
Therefore, in many cases the barbed wire fence is replaced by a plain metal wire, but this solution is questionable since such a wire has a poor visibility. Under these conditions, manufacturers have been led to develop devices which are very easy to use and comprise essentially an electrified tape. This tape is both light in weight and its width must be sufficient to make it visible from a reasonable distance. It should be made of a conspicuous, strong and rot-proof material. These properties are found mainly in synthetic materials which are electrically non-conducting substances. Therefore, plastic materials such as polyethylene or the like must be associated with a metal wire for obtaining an electrified tape.
Experience teaches that several wires are necessary for palliating any failure or breakage of one of them.
At present it is known to use woven tapes made as a rule of three metal wires to form the warp. However, this structure has a poor tensile strength. In fact, when the tape is stretched, it is the less elastic warp threads, namely the three metal wires, that are stressed. This poor distribution of the tractive effort led manufacturers to develop a different structure in the making of electrified tapes.
This structure consists essentially of braid in which conducting wires are incorporated. Since these conducting wires are not disposed with a longitudinal orientation in the braided tape, they can yield and elongate when a tractive effort is exerted on the tape. Therefore, this type of tape offers a good resistance. However, braiding is objectionable since it is subject to permanent distortion, notably when a braid is pulled. In this case, the wires are caused to close up, thus reducing the tape width and when the tractive effort is released, the tape does not resume its original width. This is particularly troublesome when it is desired to preserve a good tape visibility. Practical tests proved that the tape width could thus be reduced by up to 50 percent, with a consequential irreversible or permanent elongation, which is also detrimental.